Printing method and apparatus



May 17, 1932. v A. R; TRlST v 1,858,909 A PRINTING METHOD AND APPARATUS Filed July 25, 1950 ll l v`MII Il vvvntoz ifmzdimf Patented May 17, 1932 UNITED STATES PATENT OFFICE ARTHUR RONALD TRIST, OF LONDON, ENGLAND, ASSIGN 01?',` BY MFSNE ASSIGNMENTS, TO PANTONE CORPORATION, F NEW YORK, N. Y., A CORPORATION OF DLAWARE PRINTING METHOD AND APPARATUS Application led Iulyg2r5, 1930. Serial No, 470,571.

This invention relates to methods and apparatus to be used in conjunction with printing plates, and relates more particularly to methods and apparatus to be used in conjunction with printing plates having mercurialized non-printing areas.

As explained in my co-pending applica.

tion, Serial No. 182,059,1filed April 8, 1927,

l have developed printing platesiiaving nonmercurialized ink retaining areas of chromium and mercurialized ink refusing areas of mercurial amalgam. The mercurialized areas are non-printing areas, and the nonmercurialized areas are the. printing areas. To prevent the printing ink from being taken up by the mercurialized areas, it is necessary to feed a small quantity of mercury to the mercurialized areas during the printing op-l eration. One successful way of doing this is to feed the mercury suspended in a suitable ink to the mercurialized areas of the printing plate. This method has been describedA in my copending application, Serial No. 323,580, filed December, 1928. l

y According to the present invention, a new form of rolling contactV brush is made to brush lightly overthe polished ink rejecting surfaces so as to prevent tarnishing, and also" to feed mechanically the required amount of mercury to the `surface of the mercurialized areas of the printing plates. An object of the invention is t0 prevent tarnishing of the polished areas of printin plates. Another object of the invention is to mechanically feed mercury to the mercurialized areas of printing plates in sutllciently minute and-properly distributed quantities.

The invention will now be described'with reference to the drawings, of which:

Fig. 1 is a side view in section of a rolling contact brush according to this invention;

Fig. 2 is a. partial side view of the water feed tubes of Fig. 1; and

' Fig. 3 is an end view of the roller of Fig. 1 arranged above a printing plate.

The steel tube 5 provided with perforations 6 is supported b v the bearings 7 and adapted w able power source.

to be revolved b v the pulley 8 from a suit- The tube 5 is covered.

with the napped fabric 9 which has on its upper surface the fibrous-like hairs or nap 10.

The stationary perforated tube 11 provided with perforations 12 is placed longitudinally along the center of tube 5 and is connected at one end with the water nozzle 13 and has its other end closed off by the cap 20. Fitting tightly over the tube 11 is the similarl tube 14 having perforations 15, the tube 14 being adapted to be revolved by means ofthe lever arm V16, and the perforations 15 of the tube 14, and the perforations 12'of the tube 11l being so staggered with respect to each other, that only one perforation 15 of the tube 14 will be in line with a perforation 12 of the tube 11 for any position of the lever arm 16. Full movement of the lever arm 16 causes first one and then the other of the perforations of the tubes to be in line until after complete travel of the lever all of the perforations have been successively in ali ent. Arranged between the tube 14 and the tube 5 are the two tubes 16 and 17 which are of fine mesh wire gauze. Contained between the w1re gauze tubes 16 and 17 are fabric layers 21 containing between thema mixture of mercury and chalk which is triturated together to form hydrargyrum cum creta or what is commonly known as gray powder. This powder comprises metallic mercury in a state of such fine subdivision that the material can be made into a loose paste-by the addition of a water spray only.

In operation, the roller 5 is revolved at high speed. It has been found that a speed i of about 1000 revolutions per minute is satisfactory. The position ofthe roller 5 with rev spect tothe printing plate 18 (Fig. 3) is so mercurialized areas of the printing plate noty having any anity for ink, has, under certain atmospheric conditions at high temperatures, a tendency to tarnish. AThis tarnish or slight oxidation is effectively cured or prevented by the light brush-like action of the spinning brush roller, especially as mercury gand water vapor is fed to it.

Atomized water under pressure is fed to the nozzle 13 and fills the space within the tube 11 when the lever 16 is operated to place the apertures12 of the tube 11 in line with the apertures 15 of the tube 14. The water vapor passing through the aligned apertures is projected through the mercurial mixture between the wire gauze tubes 16 and 17 and produces a spray containing moistened metallic mercury which passes through the aperture 6 of the tube 5 into the plush-like fabric contained thereon. The mercury and spray then'reaches the surface of the brush roller and contacts with the mercurialized areas of the printing plate to maintain the plate in perfect printing condltion.

It has been found that the amount of mer'- V cury required is probably only two or three drops for many hundred impressions once the plate has been charged. Accordmgly 'the lever 16 may be manually operated from time tor time as in the judgment of the operator of the machine the plate requires recharging. Obviously, of course, the adjustment of the control lever 16 may be made automatic by suitably gearing to the printing press.

Thel character of the base of the fabric, which is a long haired plush or other suitable material, should be such that the chalk 1tself passes with diiculty through the pores of the fabric, but the high speed of the brush roller combined with the great density of the mercury causes 'the tiny particles of the mercury and water spray to nd their way along the4 hairs of the brush onto the bright parts of the printing plate. The small particles of moisture which find their way with the mercury onto the printing plate are beneficial as the mercury 1s prevented from tarnishm'g by the presence of moisture and the lnk 1s preserved free of mercury.

The rotatable brush is rotated independently of the members of the printing press and can be run continuously or started and stopped periodically, as desired. The operation of the adjustment of the lever feed arm 16, which may be done at will, controls the feeding of the water spray to any part of the brush and this control, as well as the control of the rotation of the brush, provides complete means for controlling the exact addition of the minute quantities of mercury rel quired to keep the printing plate in proper printing condition.

Since the mercury is mixed with water spray or water vapor, it does not attach itself to the ink receivin portions ofthe late but only to the ink re using portions o the plate, so that although the mercurialized 110D.-

printing areas Aare by the feeding of the mer# cury kept in proper non-printing condition, the ink retaining or non-mercurialized portions are not interfered with.

In the foregoing description, the apparatus has been described as used foi` the purposes of preventing tarnishing of the polished areas of the printing plates and for Isupplying minute particles of mercury to the mercurialized areas of the printing plates. The apparatus may be also used, however, lfor another purpose, and its use for the purpose now to be described is a part of the invention herein disclosed. In lithographic printing, a dampening roller in intimate contact is used for dampening the lithographie plate. There is considerable frictionA developed between the contact of the dampening rollersv and the lithographic plates, which friction is considered to be disadvantageous. According to another feature of this invention, it is proposed that the rapidly revolving brush of this invention be used to feed water to a lithographic plate by hair contact. The embodiment of the invention illustrated by Figs.

1, 2, and 3 may be used for this purpose. The mercurial mixture contained between the Wire gauze tubes 16 and 17 is omitted. If the apparatus is to be used only with the lithographic plates, the wire gauze tubes 16 and 17 may be omitted and the feeding arrangement contributed by the apertured tubes 11 and 14 may, or may not, be used depending upon operating requirements. The hairs 10 on the surface of the roller are kept moistened by the action of the water spray through the openings 6, and since it is proposed that the hairs of the brush be in light contact with the lithographie plate, it is obvious that the rotating brush is effective to maintain the surfaceA of the plate effectively dampened without excessive friction.

Whereas one embodiment of the invention has been described for the purpose of illustration, it should be understood that the invention is not limited to the specic structure disclosed.

What is claimed is:

1. Printing apparatus comprising, in combination, a printing plate having mercurialized and non-mercurialized areas and a rotatable brush adapted to have its hairs make contact with the surface of said plate to prevent tarnishing of the non-mercurialized areas.

2. Printing apparatus comprising, in combination, a printing plate having mercurialized and non-mereurialized areas and a rotatable cylindrical tube having a lcovering of napped cloth with the nap contacting with the surface ofsaid plate to prevent tarnishing of the non-mercurialized areas.

3. rlhe method of supplying mercury. to mercurialized areas of a printing plate which comprises brusg mercury from a rapidly iso ized and nonmercurialized areas, a rotatable cylinder covered with napped cloth having its nap 'in light contact With the surface of said plate and means for projecting mercury onto the nap of said cloth for transmittal to the mercurialized areas of said plate.

6. Printing apparatus comprising, in combination, a printing plate having mercurialized and non-mercurialized areas, a rotatable cylinder coverd with a napped cloth having its nap in contact with the surface of said plate, a mercurial mixture Within said cylinder, and means for projecting fluid through said mixture to transmit mercury therefrom onto the nap of said cloth for transmittal to the mercurialized areas of said plate.

7. Printing apparatus comprising, in combination, a printing plate having mercurialized and non-mercurialized areas, a rotatable cylinder covered With napped cloth having its nap in light Contact With the surface of said plate, an apertured tube Within said cylinder, another apertured tube Within said first tube, a permeable mercurial mixture between said first tube and said cylinder, a fluid supply connected to said second tube, and means for aligning the apertures in said tubes whereby the fluid from said supply projects through the apertures and said permeable mixture to project mercuryonto the nap of said cloth whereby upon rotation of said cylinder the nap brushes mercury onto the surface of said plate.

8. Printing apparatus comprising, in combination, a printing plate having mercurialized `and non-mercurialized printing areas, a rotatable brush with,its hairs in contact with the surface of said plate, a fluid supply, a permeable mercurial mixture, and means for projecting fluid from said supply through said mixture onto the, hairs-of said brush so asto supply, upon rotation of said brush, mercury to themercurial areas of said plate.

9. Printing apparatus comprising, in combination, a printing plate having mercurialized and non-mercurialized printing areas, a rotatable cylinder covered with a napped cloth having its nap in light contact with the surface of said plate, a fluid supply, a

v permeable mercurial mixture Within said cylinder, and means for projecting fluid from said supply through said mixture onto the nap of said cloth so as to supply, upon ro.

tation of said cylinder, mercury to the mercurial areas of said plate.

f l0. Printing apparatus comprising, in combination, a printing plate having mercurialized and non-mercurialized areas, a rotatable cylinder covered with a napped cloth having its nap-in light contact with the surface of said plate, a permeable chamber with a mercurial mixture Within said cylinder, a fluid supply, and means for projecting fluid from said supply through said chamber whereby mercury is projected therefrom onto the nap of said cloth so that upon rotation of said cylinder, mercury is transmitted to the mercurial areas of said plate.

l1. Printing apparatus comprising, in combination, a printing plate having mercurialized and non-mercurialized printing areas, a rotatable cylinder covered with a napped cloth having its nap in light contact with the surface of said plate, a permeable cylinder` containing a mercurial mixture Within said rotatable cylinder, an apertured tube Within said permeable cylinder, another apertured tube Within said first tube, a fluid supply connected to said second tube, and means for aligning the apertures in said tubes whereby fluid from said supply is projected through said permeable cylinder to carry mercury from said supply onto the nap of said rotatable cylinder and the mercurialized surface of said plate.

12. Printing apparatus comprising, in combination, a printing plate having mercurialized and non-mercurialized areas, a rotary contact brush with its hairs in light contact with the surface of said plate, and means for supplying a mercury carrying vapor to the surface of said plate through the hairs of said brush.

13. The method of supplyingmercury to mercurialized areas of a printing plate which comprises spraying a mercury solution onto a revolving contact brush which moistens the surface of the plate with the solution.

14. The method of supplying mercury to mercurialized areas of a printing plate which comprises brushing a mercury solution from a rapidly revolving contact brush onto the surface of said plate.

In testimony whereof I allix my si nature.

ARTHUR RONALD T I S'l. 

